Depth indicator for trenching machines



1959 c. J. BROECKER 2,898,687

DEPTH INDICATOR FOR TRENCHING MACHINES Filed Aug. 9, 1956 2 Sheets-Sheet 1 INVENTOR. cam. J. Baoegnaa Aug. 11, 1959 c. .J. BRYOECKER 2,898,687

DEPTH INDICATOR FOR TRENCHING MACHINES Filed Aug. 9, 1956 2 Sheets-Sheet 2 INVENTOR. FR 6. 3 CARL J. BRoEcKEZR A'r-I-QRNEY Unite States Patent DEPTH INDICATOR FOR TRENCHING MACHINES Carl J. Broecker, Two Rivers, Wis.

Application August 9, 1956, Serial No. 602,957

Claims. (Cl. 33-185) This invention relates to a depth gage for trenching machines of the type employed in laying drain tiles. Up to the present there has been no method for the operator of a trenching machine to know when his trench was deviating from the desired depth and this frequently resulted in the tiles being laid ofi grade and necessitated reworking the job.

The principal object of this invention is to provide a gage for indicating when a trenching machine is starting to sink in the ground with consequent excessive depth of cut.

Another object of this invention is to provide a gage of the type described which can be readily modified to accommodate difierent tile sizes etc.

Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, as will obvious modifications of the single embodiment shown in the drawings in which:

Fig. l is a generally schematic view of a trenching machine provided with my invention;

Fig. 2 is an enlarged schematic View showing normal operation of my device;

Fig. 3 is similar to Fig. 2 but shows the shoe sinking with consequent increase in the depth of cut;

Fig. 4 is an end view from line 4-4 in Fig. 2;

Fig. 5 is a section taken as indicated 'by line 5-5 in Fig.4; and

Fig. 6 is a detail section showing the upper or indicating end of the present gage.

In usual operation of trenching machines the operator sets up a sight on his machine and a target at the end of the line he is to follow. As long as he keeps the sight on the target he is supposed to remain on a proper grade line. In practice, however, if the trencher as a whole or if the shoe in the soft ground the operator is misled by the target and sight system and will frequently result in digging too deep (below grade). I provide a gage which rides on top of tiles laid in the trench and will indicate any sinking of the trencher or of the shoe and Will in dicate when the depth of cut has been properly readjusted.

Fig. 1 is a greatly simplified showing of a trenching machine of the type commonly used in laying drain tiles and the like. The machine has an engine located in body 10 supported in front by wide, flat wheels 12 and in the rear on crawler tracks 14. To the rear of tracks 14 is a trenching wheel 16 having an inner ring gear 18 driven by pinion 20 which is driven by the engine through a chain drive not shown. Wheel 16 is supported on beam 22 on pinion 20 and idler Wheel 24 and is prevented from riding up by idler wheel 26 carried by struts 28, 39. Beam 22 is pivotally supported at 32 on crosshead 34 which is vertically movable on spaced pillars 36 by means of cable 38 reeved over pulley 4-0 and wound on winch 42. The rear end of beam 22 is supported by cable 44 reeved over sheave 46 and wound on winch drum 48. On hard ground the rear end of beam 22 is actually supported by shoe 50 connected to the beam by legs 52. At such times cable 44 would be slack.

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The structure described thus far is conventional. Cables 38 and 44 are adjusted to obtain the desired depth of cut below ground level 54 so the shoe 50 can ride on the grade line as shown in Figs. 1 and 2. If the ground is firm the operator then slacks ofi cable 44 so the weight of the wheel insures a good cut. The side walls 56, 56 of shoe 50 prevent collapse of the trench walls prior to placing the tiles on grade inside the shoe. Since the shoe is open at the bottom the tiles are not disturbed as the machine moves on. Drain tiles are frequently laid in quite wet ground and the shoe or the machine and shoe tend to sink in such ground. Under such conditions the grade line at the rear of the shoe will, temporarily at least, hold true whilethe shoe sinks as shown in Fig. 3. The shoe is free to sink until cable 44 is tautas shown in Fig. 3. This sinking has the efiect of lowering the trenching wheel 16 as may be seen on Fig. 3. It is this error (which, if not corrected, will get steadily worse) that I undertake to indicate so it may be corrected. T he gage on the rear of the shoe accomplishes this. I

The gage or feeler is simply in the form of a roller 58 rotatably mounted on the extreme ends of arms 60, 60 pivotally supported on pin 62 mounted inside the walls 56 of shoe 5th at the rear end thereof. The roller is adapted to ride on the top of the drain tiles already in place as may be seen in Figs. 2 to 5. Bracket 64- in the shape of an inverted channel is fixed to arms 60, 60 to transmit vertical movement of the roller to rod 66 which projects through bracket 68 fixed to the shoe. Above bracket 68 the rod may pass through a replaceable sleeve 70 the length of which is selected so the brightly colored ball or knob 72 threaded on the top of rod 66 will rest on the top of the sleeve when the shoe is riding on grade. As may be seen in Fig. 3 if shoe 5t sinks a bit the roller moves rod 66 up so ball 72 moves above the top of sleeve 70, thus indicating the shoe has sunk and correction is needed. Winch i8 is then used to lift the rear end of beam 22 until the condition has been corrected. Since the gage is located far from the trenching wheel the indicated error is magnified and the actual error will be very slight if the condition is corrected promptly. If the gage is to be used with larger diameter tile a longer sleeve is substituted and vice versa. If the machine is to be used with tile of larger diameter than will fit between the side walls of the shoe an extension foot can be fitted to the gage to extend below the roller to ride on the tops of the tiles which are then laid below the shoe bottom.

This gage has proved extremely useful in practice and tile can be laid on grade with great accuracy. Even when laying tile in ground so wet that the trench fills with water and the tiles are actually laid under water the gage permits laying tile on grade. The advantage is that tile jobs done with this aid are done right the first time and the cost is reduced.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. An indicator for a trenching machine of the type having a digging wheel followed by a shoe having vertical side walls for preventing earth falling into the trench before tile can be laid therein, comprising, a feeler adapted to ride on top of tile laid in the trench, means for mounting the feeler in said shoe while permitting vertical movement of the feeler with respect to the shoe, and indicator means responsive to said movement to indicate the movement at a point remote from the feeler.

2. An indicator according to claim 1 in which said indicator means includes a rod actuated by the feeler and projecting above the shoe where it may be seen by the operator of the machine, said indicator means including guide means adapted to I be fixed to the shoe to guide the upper end of the rod and additionally serve as a point-of-reference in observing. movementof the feeler and'rod-with respect to the shoe.

3. In a trenching machine of the type having a driver pulling a. digging device followed by an open bottom shoe having side walls for preventing vcollapse of earth into thev trench before tile can be laid in the trench, said digging device and shoe riding in the trench and supported in normal operation only at the driving. end, a device for indicatingwhen theshoe or the entire machine issinking into the-ground, comprising, vertically movable feeler means mounted in the shoe between the side walls thereof, said feeler means being adapted to ride on top of tiles laid inthe trench, transmitting. means connected to the feeler means and extending out of the. shoe to. transmit motion of the feeler means to a point remote from the feeler, and indicator means movable with the shoe and servingas a point of reference for observing motion ofthe transmitting means to thereby indicate when the shoe moves with respect to the feeler means.

4. The structure recited in claim 3 in which the transmitting means includes a rod having one end connected to the. feeler means, said indicator means movable with the shoe comprising, bracket means fixed to the shoe, the other end of said rod passing through the bracket means to be guided thereby, relative vertical motion between the feeler means and the shoe being visually observed by reference to the position of said other end of the rod with respect to the bracket means.

5. The structure of claim 4 in which the feeler means comprises'a roller rotatably mounted on arms pivotally connected to the inside of. thev shoe. walls, the bracket means including a replaceable sleeve the length of which is selected so the top ofthe rod rests on the top of the sleeve when the shoe is riding on firm ground and the roller is resting on tile of a given size.

References Cited in the file of this patent UNITED STATES PATENTS 332,042 Blickensderfer Dec. 8, 1885 375,602 Carr Dec. 27,1887 915,963 Hovland Mar. 23, 1909 2,329,659 Smith Sept; 14, 1943 2,351,792 Van Voorhis "June 20,1944 

